Given the implementation, there is nothing lightweight and low-overhead to use at build time, and at runtime how exactly is this lighter than a struct? As for self-documenting, I don't even know what it would mean here.

Remains "iterable". Given how modern compiler works, I'm still convinced you should convert plain tuples back and to a struct for source code simplicity and build time speed -- because it won't even do extra copies in most cases (and even if it does, who cares?)